1// SPDX-License-Identifier: GPL-2.0 OR MIT
  2/*
  3 * Copyright 2020 Advanced Micro Devices, Inc.
  4 *
  5 * Permission is hereby granted, free of charge, to any person obtaining a
  6 * copy of this software and associated documentation files (the "Software"),
  7 * to deal in the Software without restriction, including without limitation
  8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  9 * and/or sell copies of the Software, and to permit persons to whom the
 10 * Software is furnished to do so, subject to the following conditions:
 11 *
 12 * The above copyright notice and this permission notice shall be included in
 13 * all copies or substantial portions of the Software.
 14 *
 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 18 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 19 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 20 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 21 * OTHER DEALINGS IN THE SOFTWARE.
 22 *
 23 * Authors: Christian König
 24 */
 25
 26#ifndef __AMDGPU_RES_CURSOR_H__
 27#define __AMDGPU_RES_CURSOR_H__
 28
 29#include <drm/drm_mm.h>
 30#include <drm/ttm/ttm_resource.h>
 31#include <drm/ttm/ttm_range_manager.h>
 32
 33/* state back for walking over vram_mgr and gtt_mgr allocations */
 34struct amdgpu_res_cursor {
 35	uint64_t		start;
 36	uint64_t		size;
 37	uint64_t		remaining;
 38	struct drm_mm_node	*node;
 39};
 40
 41/**
 42 * amdgpu_res_first - initialize a amdgpu_res_cursor
 43 *
 44 * @res: TTM resource object to walk
 45 * @start: Start of the range
 46 * @size: Size of the range
 47 * @cur: cursor object to initialize
 48 *
 49 * Start walking over the range of allocations between @start and @size.
 50 */
 51static inline void amdgpu_res_first(struct ttm_resource *res,
 52				    uint64_t start, uint64_t size,
 53				    struct amdgpu_res_cursor *cur)
 54{
 55	struct drm_mm_node *node;
 56
 57	if (!res || res->mem_type == TTM_PL_SYSTEM) {
 58		cur->start = start;
 59		cur->size = size;
 60		cur->remaining = size;
 61		cur->node = NULL;
 62		WARN_ON(res && start + size > res->num_pages << PAGE_SHIFT);
 63		return;
 64	}
 65
 66	BUG_ON(start + size > res->num_pages << PAGE_SHIFT);
 67
 68	node = to_ttm_range_mgr_node(res)->mm_nodes;
 69	while (start >= node->size << PAGE_SHIFT)
 70		start -= node++->size << PAGE_SHIFT;
 71
 72	cur->start = (node->start << PAGE_SHIFT) + start;
 73	cur->size = min((node->size << PAGE_SHIFT) - start, size);
 74	cur->remaining = size;
 75	cur->node = node;
 76}
 77
 78/**
 79 * amdgpu_res_next - advance the cursor
 80 *
 81 * @cur: the cursor to advance
 82 * @size: number of bytes to move forward
 83 *
 84 * Move the cursor @size bytes forwrad, walking to the next node if necessary.
 85 */
 86static inline void amdgpu_res_next(struct amdgpu_res_cursor *cur, uint64_t size)
 87{
 88	struct drm_mm_node *node = cur->node;
 89
 90	BUG_ON(size > cur->remaining);
 91
 92	cur->remaining -= size;
 93	if (!cur->remaining)
 94		return;
 95
 96	cur->size -= size;
 97	if (cur->size) {
 98		cur->start += size;
 99		return;
100	}
101
102	cur->node = ++node;
103	cur->start = node->start << PAGE_SHIFT;
104	cur->size = min(node->size << PAGE_SHIFT, cur->remaining);
105}
106
107#endif